(Not Applicable)
1. Field of the Invention
This invention relates to wireless communication systems, and in particular to a method and apparatus for automatically configuring frequencies used by repeaters in cellular communications systems.
2. Description of Relevant Art
Wireless deployments generally require some level of frequency allocation planning (frequency planning). Frequency planning is typically performed by an RF engineer aided by specialized frequency planning software. Planning software allows estimation of RF propagation levels using models such as link budget models. A frequency plan is determined by also considering and balancing factors including coverage objectives, a carrier density objective (capacity) to serve a given population and the resulting interference ratios from implementation of that plan (quality of service). An acceptable frequency plan provides adequate performance on all the above issues.
The resulting frequency plan is generally programmed into an operation and maintenance center for radio (OMCR). A given frequency plan normally dictates an entire base station system (BSS) coverage area which includes a plurality of base transceiver systems (BTSs). OMCRs generally support a plurality of BTSs. The frequency plan containing configuration data is generally downloaded to the BTSs via a data link which can be fixed (e.g. T1) or wireless. If a wireless data link is used, the data link used to transmit frequency plan information to each BTS is not xe2x80x9cin-band.xe2x80x9d As used herein, the term xe2x80x9cin-bandxe2x80x9d refers to carrier frequencies that are within the frequency spectrum allocation assigned to the service provider for providing cellular communications services to mobile subscribers.
The frequency configuration data is transferred to the BTS over the selected data link from a central location. The data link itself generally never changes. For example, if a wireless microwave link is used, the microwave frequency used will not change when the frequency configuration of the BTS changes.
Frequency plans are created for a given coverage area and are subject to change. For example, as one or more BTSs or carrier frequencies are added, removed or physically relocated, frequency plans must generally be updated. Frequency plans may also be changed to optimize capacity, coverage or quality of service, or all of these factors simultaneously.
Some cellular systems advantageously include repeaters in addition to BTSs. For example, when a wireless system is first installed, the demand for its use in most cells can be relatively low. Because only a few cells at high expected traffic demand locations (such as at a freeway intersection) can justify the expense of a build-out deploying a high capacity BTS per cell, a service provider can opt to extend the service area and efficiency of a given BTS through use of comparatively low cost repeaters. A preferred type of repeater is a translating repeater. Translating repeaters minimize undesirable multi-path effects compared to non-translating repeaters. Using repeaters, a home base station location is identified within each cluster of cells, rather than by deployment of a complete suite of broadband base station equipment in each cell in the cluster. A plurality of inexpensive translating repeater units can be located in the low traffic density cells and serviced by a home base station. Communications between base stations and translating repeaters is generally referred to as backhaul communications, while communications between translating repeaters and mobile users is generally referred to as groundlink communications.
When initially deployed in the field, current translating repeaters are not preconfigured to transmit and receive signals on specific frequencies for both groundlink and backhaul channel communications. As noted earlier, these specific frequencies are allocated to translating repeaters based on a given frequency allocation plan. Thus, to configure the frequencies for a translating repeater, a technician is required to manually set the frequencies for use by each translating repeater. The configuration provides the translating repeater with one or more groundlink channels for communicating with mobile stations within the translating repeater""s coverage area. The technician is also required to manually configure one or more backhaul channels for the translating repeater communications with the BTS with which it is affiliated.
An installation technician typically manually configures specific translating repeater backhaul and groundlink channels from the cellular system""s frequency plan by traveling to each translator repeater site. Once on site, the technician generally uses a laptop or handheld computer which can be hardwire connected to the translating repeater through a serial port to input the required frequencies.
The installation technician must be trained to configure these frequency channels and test the resulting configuration to ensure that the desired configuration is actually realized. Training installation technicians can be costly. Moreover, there may be subsequent changes in the frequency plan affecting cells in which translating repeaters are situated. As in the initial configuration situation, a technician is required to travel to the affected translating repeater sites to manually reconfigure the groundlink and backhaul channels. Thus, manually configuring or reconfiguring translating repeater frequencies is generally an expensive and time-consuming task.
If the groundlink and backhaul channel frequencies of translating repeaters were not required to be manually set, the efficiency of both configuration and reconfiguration of the groundlink and/or backhaul frequency channels allocated to translating repeaters could be greatly improved. A method and apparatus for automatically configuring groundlink and backhaul frequencies for translating repeaters using wireless signaling would save both time and money, compared to manual configurations.
The invention concerns a method and apparatus for automatically configuring a wireless repeater in a cellular communication system. The method comprises the steps of selecting a repeater configuration associated with at least one predetermined cell, identifying a specific repeater installed in the predetermined cell, and providing the repeater configuration to the specific repeater using a wireless transmission from a remote control facility. The repeater configuration can include at least one selected from the group consisting of a neighbor list, at least one groundlink channel, at least one backhaul channel, handover thresholds, alarm thresholds, alarm masks and at least one backhaul power level.
The method can further comprise the step of storing the repeater configuration at the remote control facility. The remote control facility can be a base transceiver station (BTS). The specified repeater can identify the repeater configuration it is intended to use through the time interval used by the BTS wireless transmission or through receiving an identifying code included in the BTS wireless transmission.
The providing of the repeater configuration can be responsive to a wireless configuration request transmitted by the specified repeater. The specified repeater can be identified from the configuration request. The channel to be used for transmission of the repeater""s configuration request can be identified by the specified repeater by scanning through a list of frequencies transmitted by the BTS. The configuration request can be transmitted over at least one control channel. Alternatively, the configuration request can be sent over a channel reserved for configuration requests.
An apparatus for automatically configuring a wireless repeater in a cellular communication system comprises a structure for selecting a repeater configuration associated with at least one predetermined cell, a structure for identifying a specific repeater installed in the predetermined cell, and a structure for providing the repeater configuration to the specific repeater using a wireless transmission from a remote control facility. The repeater configuration can include at least one selected from the group consisting of a neighbor list, at least one groundlink channel, at least one backhaul channel, handover thresholds, alarm thresholds, alarm masks and at least one backhaul power level. The apparatus for automatically configuring a repeater can further comprise a structure for storing the repeater configuration at the remote control facility.
The remote control facility can be a BTS. The specified repeater can identify the repeater configuration through the time interval used by the BTS wireless transmission. Alternatively, the specified repeater can identify the repeater configuration through receipt of a signal which includes an identifying code included in the BTS wireless transmission. The structure for providing the repeater configuration can transmit a signal responsive to a wireless configuration request transmitted by a specified repeater. The specified repeater can be identified from the configuration request. The configuration request can include an electronic serial number (ESN) assigned to a specified repeater. The specified repeater can be identified through a time interval used during transmission of the configuration request. The configuration request can be transmitted over a channel identified by the specified repeater by scanning through a list of frequencies transmitted by the BTS. The configuration request can be transmitted over at least one control channel. The configuration request can also be sent over a channel reserved for configuration requests.